100 ZOOLOGICAL COLLECTIONS MADE DURING [Jail. 4, 



there are, however, about twice as many of these projections in the 

 interradial as in the radial bands. There are no spines or other 

 processes on the dorsal aspect of the arm, which is only closely 

 granulated ; no indication of any banded arrangement of the granules 

 in correspondence with the joints of the arms can be made out till 

 the third bifurcation is passed. The tentacle-scales are ordinarily 

 arranged in fours, and are short, spiniform, and subequal ; the pore 

 nearest to the mouth seems to be always without the scale; the next 

 may or may not have one ; the third has one ; the fourtii or fifth 

 pore has two, the seventh or eighth three, and the tenth or eleventh 

 four. The arms completely white, as are the radial ribs and the 

 edges of the genital slits ; the rest of the disk is of a brown colour, 

 which is reHeved by the white spinous granules. 



The smaller of the two specimens of A. ponrtalesi (Lyman) had 

 the diameter of its disk (63 millims.) nearly 20 millims. longer than 

 the specimen now under examination ; and it is possible that the 

 affinity between the two species may hereafter be shown to be closer 

 than we are yet justified in supposing it to be. Whatever the result, 

 the suspicion induces me to place with A. lymani a second and 

 smaller example of the same genus. It is to be distinguished from 

 it by several points, but every one of them may, I think, be more 

 rightly ascribed to differences in age and in sexual condition than to 

 inherited distinguishing characteristics : — 



(1) The mouth-slits are very distinctly rounded ; and the whole 

 actinostome forms a rosette. 



(2) The interbrachial spaces are sharply incised at the edge of 

 the disk. 



(3) The radial ribs, though distinct, are not prominent ; and the 

 granulation on them and on the interradial spaces of either surface 

 is less differentiated than in the larger form. 



(4) Transverse bands of granules can be detected on the dorsal 

 surface of the arms quite close to the disk. 



(5) The fifth difference lies in the smaller number of the tentacle- 

 scales ; and that is one of far greater importance than any of the pre- 

 ceding differences : most of the tentacle-scales are arranged three in 

 a row. 



Perhaps a larger series may, contrary to what ordinarily happens, 

 enable us to definitely distinguish tlie two forms. 



The larger specimen was taken in Trinidad Channel, at a depth 

 of 30 fathoms ; bottom, sand. The smaller at Port Rosario, 2-30 

 fms. ; bottom, sand and rock. 



HOLOTHUROIDA. 



As I have already remarked, this class is very feebly represented. 

 I have here only to direct attention to two species. 



CUVIERIA ANTARCTICA. 



This species, first described by Philippi (Arch. f. Nat. 1857, 

 p. 133), has since been recorded by Studer (Monatsb. Ak. Berl. 



